At what RPM do we need to get to for the trans wont downshift?

If your truck downshifts on the dyno you will see a spike in the graph, this will not give you a true hp rating, stop the pull and start over.

 

you need to run up to about 60mph

 

Don't know how relevant it is, but you can get true RPM reading with the converter locked by tapping into the TSS on the top of the tranny also. I have many times said the OD off button is useless, I stand corrected, it is good for dyno pulls to disable 4th gear, I've yet to find many other uses for it.

G

 

Many people on here race down the 1/4 with OD off.

I don't think it hurts unless you’re running so fast that you need to shift into OD, but most aren't running that fast.

I know that you mostly deal with transmissions, but can you tell me why the truck runs richer the higher the gear? Is it the more load on the motor the more fuel it needs? If that is so, than in lower gears will a lean mixture (comparatively speaking) be ok?

Thanks
Mike

 

My 3rd gears shifts at 133 mph at about close to 6k rpms.

 

Sal explained it perfect......

I have to argue w/ that chart,
I personally have done 130+ in 3rd gear
Ok it was by mistake, and ok the tach was pinned pretty
much at 6000 RPM, but I did do it

(and for those about to ask, YES my truck use to pin the tach at 6000 RPM before shifting) I ran my L like that for at least 1-1/2 yrs. (and NO, my L DOES NOT shut fuel off @5250 RPM, that was the first thing I changed when I chipped my L 2-1/2 yrs ago)